Water, sewer, and drainage pipe are laid in excavated trenches, sewer, and drainage starting from a manhole and water usually starting from an existing pipeline and working outwardly. As a pipe section is joined to another pipe section, the trench is further excavated while the previous pipe is being backfilled in an ongoing process. During the excavation for the next section, the previously laid pipe is subject to contamination due to particulate matter from backfilling of the previous pipe as well as from ongoing excavation. In most instances, this requires the wiping and brushing of the inside of the already laid end of the pipe which is a time consuming and inconvenient process. In some installations, the process of cleaning can take upwards of three minutes which, under current conditions can result in additional cost on the order of many dollars per minute.
If the individual sections of pipe are not cleaned during installation, the result is often failure of a subsequent leak test. Moreover, contaminants are of a more troublesome nature in the laying of water pipe, since the pipe, after installation must be sterilized or cleaned with chlorine. If dirt is not totally removed from a water line, it will eventually work into individual faucets and plumbing fixtures alike. Moreover, there is no protection for pipe during installation against airborne contaminants when the pipe is lying around or in fact protection against urine from animals or humans.
Another problem is safety. While a pipe layer is cleaning the bell of a pipe, he or she is usually on their knees or bent over in the trench. While their eyes are focused on the bell, they are cleaning and lubricating, and they obviously cannot be aware of any shifting of the open excavation. This means that they could be caught in a cave-in and could be in a very poor situation for escaping.
As shown in U.S. Pat. Nos. 2,708,950; 2,942,625; and 4,717,608, in the past there have been both protective caps and coverings for pipes, with U.S. Pat. No. 4,168,726 indicating a bag-type device over the end of a test port having a securing steel band for the bag.
With respect to heat shrinkable material and the sealing of pipes in the form of a cap, U.S. Pat. No. 4,569,868 indicates a tubular cap in which an intermediate section has sections of the device. Also, U.S. Pat. No. 4,300,328 illustrates the utilization of heat shrinkable material around a wire in which the material is removable through the longitudinal splitting of the cylindrical tube by virtue of a longitudinally-running wire within the material. Note U.S. Pat. Nos. 4,386,984; 4,163,117; and 4,297,155 also show heat shrink material. Note that U.S. Pat. No. 4,158,407 indicates the sealing of a journal through the utilization of a journal guard which is secured at its distal end via a band.
Other U.S. Patents relating to the sealing of pipes, albeit not at their ends, include U.S. Pat. Nos. 4,699,821; 4,532,168; 4,442,153; 4,442,154; 4,442,155; 4,802,509; 4,517,234; 4,472,468; 4,371,578; and 4,731,273.
While the above patents do not relate specifically to the utilization of shrink wrap material for the ends of conduits to prevent internal contamination of the conduit during pipe laying, U.S Pat. No. 4,757,595 illustrates the utilization of shrink wrap for protecting the outside threads of a drill pipe. It will be appreciated that this patent is directed to problems associated not with internal contamination of pipes due to the drilling operation, but rather the integrity of external threads on a pipe which, as will be appreciated, are joined together at a drill site through the threading of one pipe onto another.
This patent is not directed to gasketed slip joint applications which are common in the laying of water and sewer pipe in which an end of one pipe is inserted into the aperture and of another pipe and is press fit thereinto by virtue of an internal O-ring gasketing arrangement. There are no external threads and no threading problem whatsoever with respect to the installation of water and sewer pipe.
Moreover, this latter-mentioned patent does not involve the removal of the shrink wrap material by cutting a circumferential aperture in the end of the material so as to permit the introduction of a mating slip joint pipe end into the previously sealed end of a pipe. Thus, a simple system of shrink wrap removal is not shown in this patent, it being understood that the entire shrink wrap assembly must be removed to permit the pipe threading operation.
It will thus be appreciated that U.S. Pat. No. 4,757,595 does not address or solve the problems of pipe laying, but rather solves a different problem involved with the exterior threads in an oil well drilling application.